Study On Purification And Stability Of Phycocyanin In Spirulina

Phycocyanin, as a kind of natural pigment, is extracted from algae. It is of numerous medicinal efficacy and physiological function and it is also safe. Phycocyanin is widely used in many fields, including food, medicine, biology, cosmetics, etc. Now, the hot research spot is the large-scale production of phycocyanin.The purpose of the paper is to optimize the extraction and purification process of the phycocyanin to realize industrialized production, which used DunDing spirulina as the material. Then a kind of method was chosen to improve stability of phycocyanin by researching the effect of each factor to it, and the stabilized phycocyanin was applied to food.The method of ultrasonication was chosen to the extraction of phycocyanin, after comparing three methods of ultrasonication, freezing-thawing and magnetic stirring, respectively. Through the single factor and orthogonal experiments, extraction efficiency was the evaluation indexes, and the specific process was:ultrasonic power 650W, extraction time 1.5h, extraction temperature 35℃, solid-liquid ratio 1:50, pH value 7.0.Purification was divided into protein precipitation and ultrafiltration purification. Three methods were compared in preliminary purification, included ammonium sulfate fractional precipitation, chitosan affinity precipitation and isoelectric precipitation. Then ammonium sulfate fractional precipitation was chosen, and the purity ratio (A620/A280) and phycocyanin recovery was the evaluation indexes. The saturation scope was 20%-50%, the purity ratio (A620/A280) was 1.28 and phycocyanin recovery rate was 87.8% by the protein precipitation. Ultrafiltration was used to the further purification, and the process conditions were determined by the single factor experiments. The process conditions were:molecular weight of the ultrafiltration membrane 30k, the time of ultrafiltration for once, pressure 0.06 MPa, sample concentration 0.05 mg/mL (refers to phycocyanin). After the two steps of purified, the purity ratio (A620/A280) of the sample reached 1.72 which achieved food grade (0.7), and the recovery rate was 76.7%.The method of air suspension was chosen to make phycocyanin microcapsules by two steps of granulating-coating in order to improve the stability of the phycocyanin. Water soluble starch was used as auxiliary material on granulating, and gelatin and malt dextrin was used as wall materials. Through the single factor and orthogonal experiments, the coating process conditions were determined:inlet air temperature 80℃, the ratio of core-material to wall-material (W/W) 1:1.5, atomization pressure 0.15 MPa, the gelatin content of the wall material 20%. Under these conditions, the application stability and storage stability improved by 26.21% and 75.1%, respectively.The microencapsulation of phycocyanin was applied to solid beverage. Through the single factor and orthogonal experiments, the additives of every composition in the solid beverage were determined:sugar 40%, CMC-Na 1%, blueberry essence 0.3%, phycocyanin microcapsule 35%, others needed polish to 100% with malt dextrin. Phycocyanin solid beverage was proofed to have certain antioxidant effect through the clear hydroxy free radical experiment.